Counter ejector

ABSTRACT

The elevator of a counter ejector is permitted to descend a predetermined distance in seriatim movements by means of a hydraulic circuitry cooperating with a parallelogram linkage support for the elevator. While a stack of boxes is being removed from the elevator, incoming folded boxes are intercepted by fingers which also direct a blast of air downwardly against the top of the stack.

United States Patent n 1 Grobman 451 July 1, 1975 1 1 COUNTER EJECTOR [75] lnvcntor: William Grobman, Philadelphia, Pa.

[73] Assignee: Molins Machine Company, Inc., Camden, NJ.

122] Filed: Jan. 14, I974 [21 I Appl. No.: 433,328

[52] US. Cl. 93/93 C; 93/93 DP; 214/6 H; 271/195; 271/218 [51] Int. Cl .1. B31b 1/98 [58] Field of Search 93/93 R, 93 C. 93 DP; 214/6 H; 271/189. 195 217, 218, 220

1561 References Cited UNITED STATES PATENTS 2,619.902 12/1952 Hunziker 271/195 X 3,150,578 9/1964 Dale ct a1 214/6 H X Mays 214/6 H 3.537.704 11/1970 Bond 271/221) X 3,580.402 5/1971 Tolf et a1. r 214/6 H X 3,679,072 7/1972 Mueller v 271/218 X 3.712.186 1/1973 Lulic ct a1. 93/93 DP X Primary Examiner-Roy Lake Assistant ExaminerJames F. Coan Attorney. Agent. or FirmSeidel. Gonda & Goldhammer [57] ABSTRACT The elevator of a counter ejector is permitted to descend a predetennined distance in seriatim movements by means of a hydraulic circuitry cooperating with a parallelogram linkage support for the elevator. While a stack of boxes is being removed from the elevator. incoming folded boxes are intercepted by fingers which also direct a blast of air downwardly against the top of the stack.

19 Claims, 9 Drawing Figures WF -Wmm 1 SHEET WmQ COUNTER EJECTOR This invention is directed to a counter ejector, namely apparatus which accumulates a number of sheets of accurate count in a stack on an elevator. and then ejects the stack while a new stack is accumulating. The sheets are preferably folded, collapsed paperboard boxes having their adjacent edges taped, glued or otherwise joined. The collapsed boxes are formed in a folder-gluer machine and then conveyed to the counter ejector. The elevator descends with seriatim movements as the stack accumulates thereon. When the elevator reaches its lowermost position, the stack is transferred to a conveyor and the elevator then ascends to receive a new partially accumulated stack.

A large number of counter ejectors have been proposed heretofore. Most of such counter ejectors were too complex and/or not capable of handling the inconsistencies inherent in manufacturing folded, glued corrugated boxes.

The counter ejector of the present invention includes a conveyor for feeding the folded boxes to the platform of an elevator. The elevator is preferably supported by a fluid cylinder connected to a parallelgram linkage. The elevator preferably descends under the control of a hydraulic circuit which periodically meters out a portion of hydraulic fluid in the cylinder supporting the elevator in response to a signal from a counter.

While the stack of boxes is on the elevator, a blower such as described in US. Pat. No. 3,292,503 causes an airstream to be directed downwardly to the top of the stack to keep the boxes under compression. If the boxes open, the newly bonded joint between adjacent edges of the collapsed box would be broken.

When the preselected number of boxes to form a bundle has accumulated in a stack on the elevator, fingers are moved to an extended operative position over the stack to intercept the continuous stream of boxes. The fingers are constructed and arranged to direct a stream of air downwardly onto the top of the stack supported by the elevator. After the fingers have reached the operative position, the elevator descends rapidly to a position in which its platform is adjacent a discharge conveyor. The stack is transferred off the elevator onto the discharge conveyor. After transfer of the stack, the elevator ascends to a position to receive the partially accumulated stack from the fingers which thereafter retract to an inoperative position. The fingers are preferably mounted on a common support movable toward and from the elevator support frame.

It is an object of the present invention to provide a counter ejector which is reliable, relatively simple and requires minimum maintenance.

It is another object of the present invention to provide a counter ejector with an elevator which descends successively in response to the number of boxes accumulated thereon.

It is another object of the present invention to provide a counter ejector having novel means for causing the elevator to move upwardly and downwardly.

It is another object of the present invention to provide a counter ejector wherein air pressure means is utilized to inhibit opening of folded, glued paperboard boxes.

Other objects will appear hereinafter.

For the purpose of illustrating the invention, there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

FIG. I is a side elevation view of a counter ejector in accordance with the present invention.

FIG. 2 is a sectional view taken along the line 22 in FIG. I but on an enlarged scale.

FIG. 3 is a sectional view taken along the line 3-3 in FIG. 2.

FIG. 4 is a sectional view taken along the line 4-4 in FIG. 1 but on an enlarged scale.

FIG. 5 is a sectional view taken along the line 5-5 in FIG. 4 but on an enlarged scale.

FIG. 6 is a timing chart.

FIG. 7 is a diagrammatic illustration of pneumatic circuitry forming a part of the present invention.

FIG. 8 is a diagrammatic illustration of hydraulic circuitry forming a part of the present invention.

FIG. 9 is an alternative arrangement wherein a valve forming a part of FIG. 8 may be cam operated.

Referring to the drawing in detail, wherein like nu merals indicate like elements, there is shown in FIG. I a counter ejector in accordance with the present invention designated generally as 10.

The counter ejector 10 includes a stationary frame designated generally as 12 and having frame sides 13 and I3. Folded paperboard boxes are delivered to the counter ejector 10 in any desired manner such as by the coacting conveyor belts I4 and 16. The counter ejector 10 includes an elevator 18 for receiving boxes from the conveyor belts l4 and I6 and transferring them to the discharge conveyor 20. The conveyor 20 extends between the upright frame portions on a frame 22 which is mounted on wheels 24. The wheels 24 travel on rails 26 so that the distance of the frame 22 from the frame 12 may be varied as will be described in greater detail hereinafter.

The mechanical details of the elevator 18 are as follows. Elevator 18 includes a pair of horizontally disposed shafts 28 and 30. See FIGS. 2 and 3. A plurality of generally T-shaped plate members 32, 33, 34 and 35 are disposed parallel to one another. The shafts 28 and 30 extend through aligned holes in the upright portion or leg of said members 32 35. Each of the members 32-35 is provided with a portion defining a horizontal support surface 36. Hence, the support surface 36 for a stack is defined by a plurality of spaced parallel surfaces.

A parallelogram linkage support mechanism is provided for the members 32-35. Thus, link members 38 and 39 have one end pivotably connected to the shaft 28 and another end pivotably connected to a horizontally disposed shaft 42 supported by the frame 12. Link members 40 and 41 have one end pivotably connected to shaft 30 and another end pivotably connected to shaft 44. Shaft 44 is beneath shaft 42 and supported by the frame 12. The distance between shafts 28 and 30 corresponds to the distance between shafts 42 and 44. Also, the link members 3841 are of the same length. Thus, as the elevator I8 moves up and down due to pivotable movement of the link members 38-41, the support surfaces 36 remain horizontal.

A single motor means may be utilized to cause pivotable movement of the link members 3841 to attain the up and down movement of the elevator 18. I prefer to use separate motor means. Thus, a pneumatic cylinder 46 has one end pivotably connected to a rigid structural portion of the frame 12. A piston rod 48 extends from the other end of the cylinder 46 and is pivotably coupled to the link member 40. Cylinder 46 is utilized to cause the elevator 18 to move upwardly. Circuitry associated with cylinder 46 is illustrated in FIG. 7 and will be described in detail hereinafter.

A cylinder 50 has one end pivotably connected to a structural portion of the frame 12. The other end of the cylinder 50 has a piston rod 52 which is pivotably connected to the link member 41. Cylinder 50 is a hydraulic cylinder and is utilized to support the elevator. Hydraulic circuitry including a shuttle valve is associated with cylinder 50 as shown in FIG. 8 and will be described in detail hereinafter. In FIG. 3, the uppermost and lowermost positions of the elevator 18 are shown in phantom.

Folded paperboard boxes delivered to the elevator 18 by the conveyor belts 14 and 16 are discharged into the space above the elevator 18 as indicated by the arrow 54. When following the trajectory of arrow 54, the boxes contact the backstop 56 supported by the frame 22. Since the frame 22 is adjustable with respect to the frame 12, the position of backstop 56 is adjustable to accommodate different box sizes. As shown more clearly in FIG. 4, the backstop 56 is comprised of a plurality of spaced upright plate members 64 which are parallel to one another and supported from the frame 22 by bracket members 66.

As the boxes are accumulated on the support surfaces 36 of the elevator 18, they form a stack 62. A spanker is provided to repetitively engage a side edge of the stack 62 and cause the opposite edge of the stack 62 to contact the backstop 56 to thereby square the panels of each box and to align the stack 62.

The spanker includes a plurality of spaced parallel spanker plates 68 having a narrow curved tongue 70 at their upper end. See FIGS. 2 and 3. The tongues 70 are received in annular notches on the shaft 72. Shaft 72 is an idler shaft supported by the frame 12 and over which the box blanks are discharged from the conveyor belts l4 and 16. The extent of movement of the spanker plates 68 is illustrated by the solid lines and phantom lines shown in FIG. 3.

Each of these spanker plates 68 is removably connected to a transverse member 74 adjacent to and parallel to the shaft 72. Member 74 is supported at the upper ends of parallel arms 76 and 78 on opposite sides of the elevator 18. See FIGS. 2 and 3. The lower end of the arms 76 and 78 are rotatably supported by a transverse shaft 80.

A means is provided to cause the arms 76 and 78 to pivot about shaft 80 in a repetitive manner. Any one of a wide variety of devices may be utilized to accomplish this function. As shown in FIG. 3, such means includes a cam 82 secured to a shaft 84. Cam 82 is eccentric with respect to the shaft and is rotatably received in a bore on a bracket 86. Bracket 86 has one end pivotably coupled to the arm 76. Hence, as shaft 84 rotates. the spaner plates 68 move from the solid line position to the phantom position shown in FIG. 3 in a repetitive manner.

A pusher means is provided to transfer a stack 62 from the elevator 18 onto the conveyor 20. Referring to FIGS. 2 and 3, there is provided an upright plate-like pusher member 88 connected to one end of a piston rod 90 extending from pneumatic cylinder 92. Cylinder 92 is mounted on a convenient portion of the frame 12 such as beam 94. Member 88 is provided at its lower end with spaced tines 96 which extend into the gap be tween adjacent ones of the members 32-35. In FIG. 3, the extended position of the pusher member 88 is shown in phantom with the retracted position shown in solid lines.

Referring to FIGS. 1 and 4, it will be noted that the conveyor 20 includes side rails 100 and 100' which rotatably support driven rollers 98 extending transversely thereacross at spaced points therealong. Rollers 98 may be driven in any convenient manner. As illustrated, the follers 98 are driven by an endless belt 102 which extends around various rollers including a roller driven by motor 104.

The initial portion of conveyor 20 is narrower than the extent of rollers 98. The initial portion includes a plurality of sets of rollers designated 106, 108, and which are preferably driven by belts 111 and motor 113. See FIG. 1. Each set of rollers 106, 108, 110 is orientated with respect to the elevator 18 so as to extend between two adjacent ones of the plate members 32-35 as will be apparent from FIG. 4.

A subframe 112 is supported by the frame 22 at an elevation above the elevation of the conveyor 20. The subframe 112 includes frame sides 114 and 116. See FIGS. 1, 4 and 5. Except for the initial portion of the subframe 112 adjacent the elevator 18, the frame sides 114 and 116 rotatably support a plurality of idler rollers 118. Said initial portion of the subframe includes a plurality of spaced parallel conveyors 120.

Each conveyor 120 includes a driven roller 122 and an idler roller 124 supported by the frame sides 114 and 116 with the elevation of roller 124 being above that of roller 122 as shown more clearly in FIG. 5.

A plurality of idler rollers 126 are supported by the frame sides I14 and 116 within the closed loop of an endless belt 128 which extends around the rollers 122 and 124. Due to the elevation of roller 124, the belt 128 includes an angled portion 129 which extends downwardly toward the conveyor 20 at an acute angle of about 30 degrees. Roller 122 is mounted on a shaft driven by motor 130 and chain 132 which are supported by one of the frame sides such as frame side 1 16.

The subframe 112 is adapted to be selectively elevated with respect to the conveyor 20. The elevating means may assume a wide variety of shapes and include a variety of different devices. In the preferred embodiment illustrated, the subframe 112 is selectively adjustable upwardly and downwardly by a means which includes a plurality of racks and pinions.

Referring to FIG. 5. the right hand end of the subframe 112 is provided with a rack 134 on one side and a corresponding rack 135 on the opposite side. The other end portion of the subframe 112 is provided with correspondingly disposed racks 136. Each of the racks 134436 is meshed with a pinion 138 mounted on a common shaft with a sprocket 140. Thus, there is a rack in each corner of the frame 22 with each such rack having associated therewith a meshing pinion 138 and juxtaposed sprocket 140.

On one side of the frame 22, a chain 142 extends around the sprockets 140. A similar chain extends around the sprockets on the opposite side of the frame 22. A hand wheel actuator 144 is coupled to a selflocking worm and worm wheel on the frame 22 for selectively rotating one of these sprockets to facilitate movement of the subframe 112 in an upward or downward direction so as to adjust the elevation of the idler rollers 118 and the angled portion 129 on the conveyors 120.

The frame 22 includes longitudinally extending side members 146 and 148 pivotably supported by the frame 22. A carriage 150 extends between the side members 146 and 148 and is supported thereby. The carriage 150 has rollers on its ends which extend into inclined tracks 152 which guide the movement of the carriage 150. Each track 152 is supported by one of the side members I46 and 148. See FIGS. 4 and 5.

A plurality of fingers 154 are supported by the carriage 150 and extend to the right in FIG. 5. The fingers 154 are preferably U-shaped and are orientated so as to extend between adjacent ones of the plates 64 as shown more clearly in FIG. 4. The fingers 154 are hollow and have a plurality of air discharge ports on their lower surface as indicated by the dots in FIG. 4 whereby air will be discharged in the direction of the arrows 156 shown in FIG. 5.

The side members 146 and 148 pivot about the transverse axis of pin 158 which pivotably couples the side member to an adjacent stationary bracket 160 on the frame 22. A link member 163 has one end pivotably connected to the bracket 160 and its other end is pivotably connected to link member 162 which is pivotably connected to the carriage 150. Line members 162 and 163 are provided for each end of the carriage 150. One link member 163 is pivotably connected to one end of a piston rod 164 which extends from a cylinder 166. Cylinder 166 has one end pivotably supported by the side member 146. A similar piston rod and cylinder is supported by the side member 148.

A cylinder 168 is pivotably supported on opposite sides of the frame 22. Each cylinder 168 has a piston rod 170 disposed in an upright direction with its free end pivotably coupled to one of the side members 146 and 148. Actuation of cylinder 168 causes the side members 146 and 148, and the elements supported thereby, to pivot about the axis of pin 158 whereby the fingers 154 may move from the elevated phantom position in FIG. 3 to the lower phantom position in FIG. 3. The purpose of such movement will be made clear hereinafter.

In FIG. 7, there is illustrated a diagrammatic illustration of pneumatic circuitry with associated controls for those components of the counter ejector which are pneumatically operated. An air supply conduit 172 is provided with a composite regulator I74. Regulator 174 may include a demister, pressure gauge, outlet pressure regulator. and flow regulator.

The conduit 172 includes an on-off supply valve 176. Valve 176 is preferably provided with a solenoid actuator and selectively communicates conduit 172 with conduit 178. In the position shown in FIG. 7, conduit 178 is vented to atmosphere through valve 176 and muffler 179. Muffler 179 muffles the high pressure air so as to attenuate noise which would otherwise be present in the form of a whistling sound upon discharge to the atmosphere.

One end of conduit 178 communicates with one side of cylinder 168 by way of a solenoid operated valve 180 and conduit 189. In the inoperative position of valve 180, said one side of the cylinder 168 is vented to atmosphere by way of conduit 189, a variable restrictor, and muffler 182. The other end of the cylinder 168 communicates with atmosphere by way of a variable restrictor and muffler 186 or by way of an inlet check valve 184 to permit air to rapidly enter the cylinder 168.

A conduit 188 extends from conduit 178 to a solenoid operated valve 190. Valve I selectively communicates conduit 188 with opposite ends of the cylinder 166 by way of conduits 194 and 196. As illustrated, conduit 188 communicates with conduit 194 while conduit 196 is vented to atmosphere by way of valve 190, a variable restrictor, and a muffler.

A flexible conduit 192 extends from a manifold on the carriage for transmitting air from conduit 194 to the fingers 154. Conduit 192 preferably has associated therewith a selectively operable flow control valve which permits cycling of the piston in cylinder 166 without any air being discharged through the fingers 154, if desired.

A conduit 198 extends from conduit 178 to solenoid operated valve 200 which, as illustrated, is in an inoperative disposition. Valve 200 selectively communicates conduit 198 with one of the conduits 202 and 204 which extend to opposite ends of the cylinder 92. When one end of the cylinder 92 is connected to high pressure air in conduit 198, the other end of the cylinder 92 is vented through one of the mufflers 206 or 208 each of which includes a variable restrictor.

The conduit 178 selectively communicates with conduit 212 by way ofa solenoid operated valve 210. Conduit 212 communicates with one end of the cylinder 46. The other end of the cylinder 46 is vented to atmosphere by way of vent 216. In the position of the valve 210 as illustrated, conduit 212 is vented to atmosphere by way of muffler 214.

FIG. 8 diagrammatically illustrates a hydraulic flow diagram in conjunction with the cylinder 50 for causing the elevator 18 to successively descend by way of circuitry which performs in the manner of a ratchet jack. A supply tank 218 of hydraulic fluid, is provided. Tank 218 is vented to atmosphere through vent 220.

The tank 218 is connected by way of conduit 226, directional valve 222, and conduit 232 to one side of a shuttle valve 224. The shuttle valve 224 includes a shuttle member or piston 230. An adjustable limit stop is provided for the piston 230 by way of hand wheel and screw 228 which may be supported on the frame side 13. Conduit 234 extends from one end of the valve 224 and communicates with conduit 236 by way of valve 222.

The conduit 236 extends from the valve 222 to one end of the cylinder 50 and contains a selectively adjustable flow regulator 238. The upper end of the cylinder 50 communicates with the supply tank 218 by way of conduits 242 and 244. Conduit 242 contains a selectively adjustable flow regulator and an associated bypass check valve, the composite of which is designated 240. Conduit 244 includes a check valve 246 which is adapted to be opened by the upward movement of the piston in cylinder 50 occasioned by the upstroke of the piston in cylinder 46 (see FIG. 7) which causes the elevator 18 to move to its uppermost position.

A conduit 248 extends between the conduits 226 and 236. Conduit 248 includes a solenoid operated valve 250 which is shown in an inoperative position. When operated. valve 250 enables the elevator to descend in a rapid uninterrupted manner.

During normal operation, the elevator 18 descends in successive stages. Such descent is preferably correlated with the depositing of collapsed boxes on the support surface 36 of the elevator 18. Thus. boxes delivered to the elevator 18 are detected by the photocell 258 and counted by the counter 256. The counter 256, after a predetermined number such as 10 boxes is counted. activates switch 254 which in turn activates the solenoid coil 252 which causes the valve 222 to shift. Every time the valve 222 shifts. a predetermined volume of the hy draulic fluid is cycled from beneath the piston in cylinder 50, by way of valves 222 and 224, to the supply tank 218.

In FIG. 9, there is illustrated an alternative embodiment for periodically shifting the valve 222. Thus. a cam follower 262 on the spool of valve 222 may be activated by a cam 260 which is driven by the folder-gluer drive. In this manner. the valve 222' will be shifted periodically as a function of the number of boxes being handled.

In FIG. 6, there is illustrated a typical timing diagram of various functions versus time in seconds. The designation fingers down" refers to fingers 154 being in the phantom horizontal position shown in FIG. 3. The designation elevator down refers to the elevator 18 being in its lowermost phantom position in FIG. 3. The designation pusher forward" refers to the pusher member 88 being in the phantom position shown in FIG. 3. The designation conveyor run" refers to conveyors 120 being driven by motor 130.

In FIG. 6, the designation pusher return refers to the pusher member 88 returning to the solid line position shown in FIG. 3. The designation elevator up refers to the elevator 18 being caused to ascend by means of the pneumatic cylinder 46. The designation fingers back refers to the fingers 154 being withdrawn from the extended position shown in FIG. 3 or FIG. 5 to the retracted position shown in FIG. 1. The designation fingers up & out" refers to the fingers 154 being in the position shown in FIG. 5 and in phantom lines at the upper end of FIG. 3.

The operation of the counter ejector is believed to be apparent to those skilled in the art in view of the preceding detailed description and the following brief description of the sequence of operations. As a starting point. assume that the elevator 18 is in its uppermost phantom position in FIG. 3 while being supported by the hydraulic cylinder 50 with all other components of FIG. 3 being in their solid line positions except for the link members 3841 which of course will be angled upwardly from right to left. Folded boxes delivered by conveyor belts 14 and 16 follow the trajectory of arrow 54, contact the backstop 56, and are deflected in the direction of arrow 58 to accumulate in a stack 62 on the support surfaces 36 of the elevator 18.

It will be noted that the support surfaces 36 are closely adjacent to the horizontal trajectory of the collapsed boxes so that there is no opportunity for the boxes to nose dive. After a predetermined number of boxes, such as 10 boxes. has accumulated on the elevator 18, valve 222 is shifted to a position wherein conduit 236 communicates with conduit 232 and conduit 234 communicates with conduit 226. In this position, the hydraulic fluid within valve 224 and to the right of piston 230 flows through conduit 226 to the supply tank 218. This allows the piston of cylinder 50 to descend a distance corresponding generally to the thickness of about 10 boxes on elevator 18. Hydraulic fluid from the cylinder 50 enters the valve 224 by way of conduits 236 and 232 to cause the piston 230 to move to the right in FIG. 8. The next time valve 222 is shifted. the components assume the position shown in FIG. 8 wherein all hydraulic fluid to the left of piston 230 is communicated to the tank 218. Thus. the elevator 18 is by way ofa hydraulic ratchet caused to period ically and successively descend an incremental distance which is a function of a predetermined number of boxes accumulating on the support surfaces 36.

As the stack 62 accumulates. the boxes are repetitively spanked by the spanker plates 68 whereby the boxes are squared. If desired. side gates may be provided to assist in aligning the boxes. Pressurized air discharged downwardly from the blower 60 keeps the boxes compressed while the stack accumulates.

After the elevator 18 has accumulated the preselected number of boxes to form a stack and has descended the necessary distance, the relay 252 is actuated by the counter 256 and causes the following events to occur. Valve 190 is activated so that pressurized air from conduit 188 flows through conduit 194. Simultaneously air is directed to fingers 154 through conduits 192 and 194 to cylinder 166. Cylinder 166, via link members 162, 163, moves carriage thereby causing fingers 154 to move toward frame 12 as shown in phantom in FIG. 3. Valve is then deactivated causing pressurized air to stop flowing from conduit 178 to conduit 189 thereby allowing the piston in cylinder 168 to descend. and the fingers 154 to lower to a horizontal position overlying the stack. Folded boxes subsequently delivered from conveyor belts 14 and 16 accumulate on fingers 154. Since such subsequent boxes will be disposed between the stack 62 and the blower 60, pressurized air is discharged through the holes on the bottom of the fingers 154 to maintain a compressive force on the boxes in the stack 62.

Actuation of relay 252 by counter 256 in a manner indicative of a complete stack also shifts selector valve 250 whereby hydraulic fluid is directed from the lower section of cylinder 50 through conduit 248 to the tank 218. This causes the elevator 18 to descend rapidly from its previous intermediate position to its lowermost or discharge position.

When the elevator 18 reaches its lowermost position wherein the surfaces 36 are meshed with the sets of idler rollers 1061 10 on the conveyor 20, a limit switch is tripped which causes the following events to occur. Valve 200 is activated so that pressurized air from conduit 198 flows through conduit 204 to move the pusher member 88 from the solid line position in FIG. 3 to the phantom position in FIG. 3. Pusher member 88 transfers the stack 62 from the elevator 18 onto the conveyor 20 with the uppermost portion of the stack being engaged by the angled portion 129 on the conveyors 120 which at this time are being driven. The conveyors 120 slightly compress the stack 62.

The pusher member 88 is immediately recycled to the solid line position shown in FIG. 3 and in doing so trips a switch which activates solenoid operated valve 210 whereby pressurized air from conduit 178 is communicated by way of conduit 212 to the cylinder 46 for the purpose of raising the elevator 18 to its uppermost position.

Pusher member 88 is perforated so as to have little air resistance as it moves between its operative and inoperative positions. If it is desired to change counter 256 for the total height of the stack 62, hand wheel 144 will be turned to raise or lower the subframe 112. As

the size of the boxes being processed changes, the frame 22 is moved toward or away from the frame 12 by rotating the lever arm 264 which rotates pinion 268 meshed with rack 266. in the event of a jam up, or for any other desired purpose, the elevator 18 may be caused to rapidly and uninterruptedly descend by manually activating the solenoid valve 250. Adjustment of hand wheel 228 adjusts the stroke of piston 230 which in turn adjusts the amount of descent of the elevator 18 each time that valve 222 is shifted. Adjustment of flow regulator 238 controls the rate at which hydraulic fluid may flow from conduit 236 to the valve 224.

Thus, it will be seen that the counter ejector of the present invention accumulates a stack 62 of boxes on the elevator 18 and periodically causes the elevator 18 to descend a predetermined distance by means of a hydraulic circuit while the stack is maintained slightly compressed due to pressurized air from blower 60. When a stack is being transferred off the elevator, fmgers 154 temporarily support the incoming boxes continuously fed to the counter ejector and the fingers also perform the function previously performed by blower 60. That is, pressurized air is discharged downwardly from the fingers 154 to maintain the stack 62 under compression until the function of compression is transferred to the conveyors 120. As previously referred to, the compression of the boxes in the stack is necessary to prevent the joint of the boxes from opening or separating.

Pallets may be stored and loaded adjacent the left hand end of the conveyor 20 in FIG. 1. If desired, the stack 62 may be tied while supported upon conveyor 22 and thereafter stacked on the pallets.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.

I claim:

1. Apparatus for accumulating a stack of sheets such as folded boxes comprising an elevator having a surface on which sheets may accumulate to form a stack, a first conveyor means for feeding sheets to said elevator, circuitry including fluid means for sequentially causing the elevator to descend in discrete increments correlated with the number of sheets fed to the elevator, sec and conveyor means for receiving a stack from said elevator, pusher means for transferring a stack from said elevator to said second conveyor means, a backstop facing said first conveyor means, and means above said elevator to apply a downwards compressive force to a stack while a stack is on the elevator.

2. Apparatus in accordance with claim 1 including a parallelogram linkage for supporting said elevator, said fluid means including a fluid cylinder coupled to said linkage.

3. Apparatus in accordance with claim 1 wherein said fluid means includes a hydraulic cylinder coupled to said elevator for controlling the descent of said elevator and a pneumatic cylinder coupled to said elevator for causing the elevator to ascend.

4. Apparatus in accordance with claim 1 wherein said means for applying a compressive force includes a blower for directing a blast of air toward the elevator.

5. Apparatus in accordance with claim 1 including a plurality of fingers mounted for reciprocation from an inactive position to an active position, said fingers being above the elevator for temporarily supporting incoming sheets when the fingers are in their active position, means for moving and guiding the fingers along an upwardly inclined plane when the fingers are moved from their inactive to their active position, and means for pivoting the fingers from an inclined position to a horizontal position when the fingers are in their active position.

6. Apparatus in accordance with claim 5 wherein said fingers are hollow and connected to a source of pressurized air associated with said circuitry, said fingers having discharge ports on a surface thereof for discharging air toward said elevator.

7. Apparatus in accordance with claim 1 including a vertically adjustable means for engaging and maintaining a compression force on a stack while the stack is supported by said second conveyor means.

8. Apparatus in accordance with claim 1 wherein said circuitry includes means for counting sheets fed to the elevator and a valve for sequentially permitting the escape of a predetermined volume of fluid whereby said elevator descends in predetermined increments.

9. Apparatus for accumulating a stack of sheets such as folded boxes comprising an elevator having a surface on which sheets may accumulate to form a stack, a first conveyor means for feeding sheets to said elevator, cir cuitry including means for sequentially causing the elevator to descend in discrete incremental distances correlated with the number of sheets fed to the elevator, second conveyor means for receiving a stack from said elevator, pusher means for transferring the stack from said elevator to said second conveyor means, a backstop facing said first conveyor means, means to apply a downward compressive force to a stack while a stack is on the elevator including a plurality of fingers selectively movable from a retracted position to an extended position, said fingers overlying the elevator in their extended position and being hollow, and said fingers having a plurality of discharge ports for directing pressurized air downwardly toward the elevator when said fingers are in their extended position.

10. In a counter ejector for forming a stack of paperboard folded boxes comprising an elevator, a first frame supporting said elevator. means adjacent one side of the elevator for delivering sheets to the elevator, a backstop adjacent an opposite side of said elevator, a plurality of fingers selectively movable from a retracted inoperative position to an extended position wherein the fingers are over the elevator, a second frame mounted for movement toward and away from said first frame, said backstop and said fingers being supported by said second frame, circuitry including a hydraulic cylinder supporting said elevator and for causing the elevator to descend in discrete increments correlated to delivery of boxes to said elevator, said circuitry including valve means for permitting escape of a predetermined volume of hydraulic fluid from a lower end of said cylinder and means for repetitively cycling said valve means, and means for transferring the stack from said elevator at a discharge position of the eleva- 11. In a counter ejector in accordance with claim 10 wherein said fingers are hollow, said circuitry including means for introducing pressurzied air into said fingers when the fingers are in their extended position only.

l l and said fingers having air discharge ports on their lower surface thereof.

12. In a counter ejector in accordance with claim wherein said circuitry includes a pneumatic cylinder for moving said elevator in an upward direction.

13. In a counter ejector in accordance with claim 10 including a parallelogram linkage extending between a frame and said elevator for supporting said elevator.

14. Apparatus in accordance with claim 10 wherein said valve means includes a cam actuated valve.

15. in a counter ejector in accordance with claim 10 wherein said valve means includes a solenoid actuated valve coupled to a counter for counting boxes delive red by said conveyor means to said elevator.

16. in a counter ejector in accordance with claim 10 including a blower supported by a frame above the elevation at which said delivery means delivers boxes to said elevator.

17. in a counter ejector for forming a stack of paperboard folded boxes comprising an elevator. means for delivering sheets to said elevator, circuitry including a hydraulic cylinder supporting said elevator and for causing the elevator to descend in increments correlated to delivery of boxes to said elevator. said circuitry including valve means for permitting escape ofa predetermined volume of hydraulic fluid from said cylinder and means for repetitively cycling said valve means,

means for transferring the stack from said elevator at a discharge position of the elevator. said elevator being defined by a plurality of spaced parallel horizontally disposed surfaces. at discharge conveyor positioned to receive a stack from the elevator in a discharge position of the elevator, said conveyor having spaced parallel portions adapted to mesh with the spaced surfaces on the elevator.

18. Apparatus in accordance with claim 17 wherein said fingers extend between portions of the backstop and in their extended position temporarily support in coming sheets while a stack is being transferred from the elevator to said second conveyor means.

19. Apparatus for accumulating a stack of sheets such as folded paperboard boxes comprising an elevator, first conveyor means for feeding sheets to the elevator, means for causing the elevator to descend as a stack of sheets accumulates on said elevator. a blower above the elevator for directing air toward the elevator to apply a compressive force to a stack on the elevator. finger means movable from a retracted position to an extended position, said finger means in its extended position being below the elevation of said blower and over said elevator. said finger means having discharge ports for directing pressurized air toward the elevator when said finger means is in its extended position. 

1. Apparatus for accumulating a stack of sheets such as folded boxes comprising an elevator having a surface on which sheets may accumulate to form a stack, a first conveyor means for feeding sheets to said elevator, circuitry including fluid means for sequentially causing the elevator to descend in discrete increments correlated with the number of sheets fed to the elevator, second conveyor means for receiving a stack from said elevator, pusher means for transferring a stack from said elevator to said second conveyor means, a backstop facing said first conveyor means, and means above said elevator to apply a downwards compressive force to a stack while a stack is on the elevator.
 2. Apparatus in accordance with claim 1 including a parallelogram linkage for supporting said elevator, said fluid means including a fluid cylinder coupled to said linkage.
 3. Apparatus in accordance with claim 1 wherein said fluid means includes a hydraulic cylinder coupled to said elevator for controlling the descent of said elevator and a pneumatic cylinder coupled to said elevator for causing the elevator to ascend.
 4. Apparatus in accordance with claim 1 wherein said means for applying a compressive force includes a blower for directing a blast of air toward the elevator.
 5. Apparatus in accordance with claim 1 including a plurality of fingers mounted for reciprocaTion from an inactive position to an active position, said fingers being above the elevator for temporarily supporting incoming sheets when the fingers are in their active position, means for moving and guiding the fingers along an upwardly inclined plane when the fingers are moved from their inactive to their active position, and means for pivoting the fingers from an inclined position to a horizontal position when the fingers are in their active position.
 6. Apparatus in accordance with claim 5 wherein said fingers are hollow and connected to a source of pressurized air associated with said circuitry, said fingers having discharge ports on a surface thereof for discharging air toward said elevator.
 7. Apparatus in accordance with claim 1 including a vertically adjustable means for engaging and maintaining a compression force on a stack while the stack is supported by said second conveyor means.
 8. Apparatus in accordance with claim 1 wherein said circuitry includes means for counting sheets fed to the elevator and a valve for sequentially permitting the escape of a predetermined volume of fluid whereby said elevator descends in predetermined increments.
 9. Apparatus for accumulating a stack of sheets such as folded boxes comprising an elevator having a surface on which sheets may accumulate to form a stack, a first conveyor means for feeding sheets to said elevator, circuitry including means for sequentially causing the elevator to descend in discrete incremental distances correlated with the number of sheets fed to the elevator, second conveyor means for receiving a stack from said elevator, pusher means for transferring the stack from said elevator to said second conveyor means, a backstop facing said first conveyor means, means to apply a downward compressive force to a stack while a stack is on the elevator including a plurality of fingers selectively movable from a retracted position to an extended position, said fingers overlying the elevator in their extended position and being hollow, and said fingers having a plurality of discharge ports for directing pressurized air downwardly toward the elevator when said fingers are in their extended position.
 10. In a counter ejector for forming a stack of paper-board folded boxes comprising an elevator, a first frame supporting said elevator, means adjacent one side of the elevator for delivering sheets to the elevator, a backstop adjacent an opposite side of said elevator, a plurality of fingers selectively movable from a retracted inoperative position to an extended position wherein the fingers are over the elevator, a second frame mounted for movement toward and away from said first frame, said backstop and said fingers being supported by said second frame, circuitry including a hydraulic cylinder supporting said elevator and for causing the elevator to descend in discrete increments correlated to delivery of boxes to said elevator, said circuitry including valve means for permitting escape of a predetermined volume of hydraulic fluid from a lower end of said cylinder and means for repetitively cycling said valve means, and means for transferring the stack from said elevator at a discharge position of the elevator.
 11. In a counter ejector in accordance with claim 10 wherein said fingers are hollow, said circuitry including means for introducing pressurzied air into said fingers when the fingers are in their extended position only, and said fingers having air discharge ports on their lower surface thereof.
 12. In a counter ejector in accordance with claim 10 wherein said circuitry includes a pneumatic cylinder for moving said elevator in an upward direction.
 13. In a counter ejector in accordance with claim 10 including a parallelogram linkage extending between a frame and said elevator for supporting said elevator.
 14. Apparatus in accordance with claim 10 wherein said valve means includes a cam actuated valve.
 15. In a counter ejector in accordance with claim 10 wherein said valve means inclUdes a solenoid actuated valve coupled to a counter for counting boxes delivered by said conveyor means to said elevator.
 16. In a counter ejector in accordance with claim 10 including a blower supported by a frame above the elevation at which said delivery means delivers boxes to said elevator.
 17. In a counter ejector for forming a stack of paper-board folded boxes comprising an elevator, means for delivering sheets to said elevator, circuitry including a hydraulic cylinder supporting said elevator and for causing the elevator to descend in increments correlated to delivery of boxes to said elevator, said circuitry including valve means for permitting escape of a predetermined volume of hydraulic fluid from said cylinder and means for repetitively cycling said valve means, means for transferring the stack from said elevator at a discharge position of the elevator, said elevator being defined by a plurality of spaced parallel horizontally disposed surfaces, a discharge conveyor positioned to receive a stack from the elevator in a discharge position of the elevator, said conveyor having spaced parallel portions adapted to mesh with the spaced surfaces on the elevator.
 18. Apparatus in accordance with claim 17 wherein said fingers extend between portions of the backstop and in their extended position temporarily support incoming sheets while a stack is being transferred from the elevator to said second conveyor means.
 19. Apparatus for accumulating a stack of sheets such as folded paperboard boxes comprising an elevator, first conveyor means for feeding sheets to the elevator, means for causing the elevator to descend as a stack of sheets accumulates on said elevator, a blower above the elevator for directing air toward the elevator to apply a compressive force to a stack on the elevator, finger means movable from a retracted position to an extended position, said finger means in its extended position being below the elevation of said blower and over said elevator, said finger means having discharge ports for directing pressurized air toward the elevator when said finger means is in its extended position. 